The synthesis of analogs and camptothecin is proposed in an effort to delineate specific structure-activity relationships of this biologically active series. The synthesis and study of isocamptothecin is also proposed. The completion of a general and comprehensive synthesis of steroids including the 19-nor series, ring A aromatics such as estrone, 20 keto series such as progesterone, C27 series such as cholesterol, and the C30 tetracyclic triterpenes such as lanosterol and euphol. Functionalization of C14 could lead to the cardiac aglycones. Total syntheses of the antitumor phytosubstances crotepoxide and vernolepin will also be studied. A new approach to ring construction by the interchange of cyclopropanes for other ring size will be continued.